Congenital Adrenal Hyperplasia

(CAH)

Definition

Congenital adrenal hyperplasia (CAH) is a group of genetic conditions. These conditions affect the adrenal glands. These glands control how the body grows and develops. There are many types of CAH. Two common forms are:

Classic CAH—more severe form

Nonclassic CAH—mild form

For some, this disorder can be life-threatening. Fortunately, proper treatment can help people with CAH lead normal, healthy lives.

Causes

CAH is a genetic disorder. It is passed from the parents to the child.

The symptoms of CAH are caused by problems in the adrenal glands. The glands main job is to make vital hormones. In CAH, the glands may have trouble making one or both of the following hormones:

Cortisol—helps the body respond to stress and infections

Aldosterone—helps the body maintain normal levels of sodium and potassium

The adrenal gland will work harder to try to produce more of the missing hormones. This can lead to an overproduction of another hormone called androgen. This hormone is present in boys and girls but is responsible for the development of male features.

Classic CAH involves low levels of cortisol, perhaps low levels of aldosterone, and high levels of androgen. With nonclassic CAH the adrenal glands may be able to create normal levels of cortisol and aldosterone but end up making extra androgen.

Risk Factors

A family history of CAH will increase your child's chance of having hte condition. People can carry the gene for CAH and not have the disorder. In this case, both parents must have the CAH gene for the child to have a 25% chance of getting CAH.

Symptoms

Symptoms can vary with the different types of CAH and sex of the child. General symptoms include:

Altered or unexpected features in newborn girls such as:

Unusual appearance of genitalia in newborn girls

Parts of the external genitalia may resemble a penis

Early signs of puberty in boys as young as two or three years old such as:

Become very muscular

Experience penis growth

Develop pubic hair

Have a deepening voice

Excessive facial and/or body hair

Fast growth compared to other children their age
(most will stop growing sooner than their peers and are often relatively short as adults)

Diagnosis

Testing may be done during pregnancy, just after birth, or after symptoms develop.

Testing may be done during pregnancy if there is a family history of CAH. Particularly if a sibling has the disease. Small samples of tissue or amniotic fluid may be removed for testing. The samples are taken by one of the following:

In the United States, all newborn children are screened for classic CAH. The test involves a heelstick to draw some blood. The blood will be examined for hormone levels.

To diagnose CAH in older children or in those that were not screened as newborns, your doctor will ask about your child’s symptoms and medical history. A physical exam will be done. Your doctor may take a small amount of blood and urine to test for hormone levels. This is often enough to make the diagnosis.

If the tests are not clear, your doctor may order genetic testing. This is done with blood tests.

Treatment

You and your child may be referred to a specialist. Talk with your doctor about the best plan for you and/or your child. With treatment, your child can have a normal life. Treatment options include:

Prenatal Treatment

If CAH is found before birth,
dexamethasone
may be used. This medication can lower the level of androgens. It may allow normal development of female genitalia. It does not stop CAH from developing.

The medication may be taken as a pill or liquid by the mother.

Medications

Most children born with CAH need to take hormone replacement medicines. These steroid medications will replace the missing hormones. The exact exact types of steroid will depend on your child's condition. The medication will also help slow the production of androgens. This will reduce the development of male features in girls.

These medications can have side effects like slowing growth or lowering bone mass. In girls, the hormone replacement can also lead to a condition called
Cushing's syndrome
. Your doctor will monitor your child. Medications will be adjusted as needed.

Cortisol is needed during stressful situations and illness. If you are taking medication to replace cortisol, you may need extra doses during stressful events. This can include surgeries or illnesses. Your doctor will make a medication plan with you.

People with classic CAH will need to continue their medication for their entire lifetime. Some children with nonclassic CAH may be able to stop medication once they are adults.

Dietary Changes

Missing aldosterone can cause a condition called salt wasting. This is a problem maintaining the correct amount of salt in the blood. It can lead to low blood pressure and a high potassium level in the blood. If you have salt wasting, you may need to add table salt to your diet.

Surgery

Surgery can correct unusually formed genitalia. It is often done when the child is between 1-3 years of age.

Prevention

CAH is an inherited disorder. There are no preventive measures.

If someone in your immediate family has CAH, talk to your doctor about genetic testing. This is important if you are expecting or planning to have a child.

Meyer-Bahlburg HFL, Dolezel D, et al. Cognitive and motor development of children with and without congenital adrenal hyperplasia after early prenatal dexamethasone.
J Clin Endo Meta
. 2004;89:610-614.

Revision Information

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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